Method of imbalance correction using a grooved disk clamp

ABSTRACT

A disk clamp that can engage a disk hub to couple a disk media to a disk hub, the disk clamp having a body portion, and a groove formed in a surface of the body portion and extending at least in a circumferential direction substantially parallel to at least a portion of the circumference of the disk clamp; and a balance weight installed in the groove formed in the surface of the disk clamp, the balance weight having a quantity of material applied in the groove. A disk drive assembly using the disk hub and a method of correcting a drive imbalance using the disk hub.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/672,668, filed Nov. 8, 2012, which is hereby incorporated byreference in its entirety.

FIELD

The present disclosure relates generally to information storage devices,and in particular to a disk drive having a disk clamp having a grooveformed therein and a method of imbalance correction using the grooveddisk clamp.

BACKGROUND

Disk drives typically include a disk clamp that provides a disk clampingforce for holding one or more disks to a hub. Thus, disk clamping isbecoming more and more important not only for regular Hard Disk Drives(HDD) performance but also under extreme conditions such as operationalshock and non-operational shock. A reliable clamping force may maintainthe integration of the whole disk pack, preventing the disk fromseparating or sliding under shock event.

FIGS. 1A and 1B show perspective and cross-sectional views of a relatedclamp 140 that could be used to provide clamping force. The clamp 140has an annular shape and one or more threads 142 formed on a radiallyinterior region 144 of the clamp. As shown in FIG. 1B, the clamp 140also has a flat upper surface 146.

Further, to reduce data streaming issues and vibrations during operationimbalances of the disk pack must be within certain imbalance tolerances.In order to correct or compensate for imbalance in the disk pack, plugsor wire pieces various size or shape may be inserted into holes providedin the disk hub to correct the mass distribution of the disk pack.

However, with decreasing form factors and tighter imbalance correctionspecifications, the effectiveness of using plugs or wire pieces insertedinto holes provided in the disk hub to correct imbalance of the wholedisk pack has been reduced.

There is therefore a need for an improved disk clamp design andimbalance correction method.

BRIEF DESCRIPTION OF THE DRAWINGS

A general architecture that implements the various features of thedisclosure will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments of the disclosure and not to limit the scope of thedisclosure. Throughout the drawings, reference numbers are reused toindicate correspondence between referenced elements.

FIG. 1A is perspective view illustrating a related disk clamp 140 foruse in a hard disk drive assembly.

FIG. 1B is a cross-section view of the related disk clamp 140 takenalong line 1B-1B′.

FIG. 2 is an exploded, perspective view generally illustrating a diskdrive including an example clamp 240 according to one or moreembodiments.

FIG. 3A is a perspective view illustrating a first example embodiment ofa disk clamp 240 for use in a hard disk drive assembly of FIG. 2.

FIG. 3B is a cross-section view of the first example embodiment of adisk clamp 240 taken along line 3B-3B′.

FIG. 4 is a perspective view of the first example embodiment of a diskclamp 240 with a quantity of material added for imbalance correction.

FIG. 5 is an enlarged perspective view of a portion 500 of the firstexample embodiment of a disk clamp 240 shown in FIG. 4 with the quantityof material added for imbalance correction.

FIG. 6 is a perspective view of the first example embodiment of a diskclamp 240 with a quantity of material added for imbalance correctionwith the disk clamp cut in half to show a cross-section.

FIG. 7 is cross-sectional view of the first example embodiment of aportion 700 of a disk clamp 240 shown in FIG. 6 with the quantity ofmaterial with the disk clamp cut in half to show a cross-section.

FIG. 8A is a cross-section view of a second example embodiment of a diskclamp 240 for use in a hard disk drive assembly of FIG. 2.

FIG. 8B is a cross-section view of the second example embodiment of adisk clamp 240 for use in a hard disk drive assembly of FIG. 2 with aquantity of material added for imbalance correction.

FIG. 9A is a cross-section view of a third example embodiment of a diskclamp 240 for use in a hard disk drive assembly of FIG. 2.

FIG. 9B is a cross-section view of the third example embodiment of adisk clamp 240 for use in a hard disk drive assembly of FIG. 2 with aquantity of material added for imbalance correction.

FIG. 10A is a cross-section view of a fourth example embodiment of adisk clamp 240 for use in a hard disk drive assembly of FIG. 2.

FIG. 10B is a cross-section view of the fourth example embodiment of adisk clamp 240 for use in a hard disk drive assembly of FIG. 2 with aquantity of material added for imbalance correction.

FIG. 11 is a perspective view illustrating an example apparatus applyingthe quantity of material to an example embodiment of a disk clamp 240according to one embodiment.

FIG. 12 illustrates a flowchart for a method of manufacturing andcorrecting imbalance of a disk drive, according to one or more exampleembodiments.

DETAILED DESCRIPTION

Referring to FIG. 2, a disk drive 100 is illustrated, according to oneembodiment. The disk drive 100 comprises a hub 102, a disk 104physically contacting and supported by at least one mounting surface(not labeled in FIG. 2) of the hub 102, and a head 106 operable to writeto and read from the disk 104. In one embodiment, the hub 102 comprisesa substantially cylindrical portion 108 which define a longitudinal axisL and a mounting surface (not labeled in FIG. 2) substantially normal tothe longitudinal axis L, the mounting surface (not labeled in FIG. 2)extending radially outward.

As illustrated herein, the disk drive 100 comprises a magnetic diskdrive, and the structures and methods described herein will be describedin terms of such a disk drive. However, these structures and methods mayalso be applied to and/or implemented in other disk drives, including,e.g., optical and magneto-optical disk drives.

The disks 104 may comprise any of a variety of magnetic or optical diskmedia having a substantially concentric opening 114 defined therethrough. Of course, in other embodiments, the disk drive 100 may includemore or fewer disks. For example, the disk drive 100 may include onedisk or it may include two or more disks. The disks 104 each include adisk surface 116, as well as an opposing disk surface not visible inFIG. 2. In one embodiment, the disk surfaces 116 comprise a plurality ofgenerally concentric tracks for storing data.

As illustrated, the hub 102 may be coupled to and support the disks 104.The hub 102 may also be rotatably attached to a motor base 118 of thedisk drive 100, and may form one component of a motor 120 (e.g., aspindle motor). The motor 120 and the hub 102 may be configured torotate the disks 104 about the longitudinal axis L.

Further, a disk clamp 240 may be coupled to the hub 102 to provide adownward clamping force to the disks 104. Specifically, the disk clamp240 may be positioned above the disks 104 and attached to the hub 102.

The disk drive 100 may further include a cover 122, which, together withthe motor base 118, may house the disks 104 and the motor 120. The diskdrive 100 may also include a head stack assembly (“HSA”) 124 rotatablyattached to the motor base 118. The HSA 124 may include an actuator 126comprising an actuator body 128 and one or more actuator arms 130extending from the actuator body 128. The actuator body 128 may furtherbe configured to rotate about an actuator pivot axis.

One or two head gimbal assemblies (“HGA”) 132 may be attached to adistal end of each actuator arm 130. Each HGA 132 includes a head 106operable to write to and read from a corresponding disk 104. The HSA 124may further include a coil 134 through which a changing electricalcurrent is passed during operation. The coil 134 interacts with one ormore magnets 136 that are attached to the motor base 118 to form a voicecoil motor (“VCM”) for controllably rotating the HSA 124.

The head 106 may comprise any of a variety of heads for writing to andreading from a disk 104. In magnetic recording applications, the head106 may include an air bearing slider and a magnetic transducer thatincludes a writer and a read element. The magnetic transducer's writermay be of a longitudinal or perpendicular design, and the read elementof the magnetic transducer may be inductive or magneto resistive. Inoptical and magneto-optical recording applications, the head may includea mirror and an objective lens for focusing laser light on to anadjacent disk surface.

The disk drive 100 may further include a printed circuit board (“PCB”)(not shown). The PCB may include, inter alia, a disk drive controllerfor controlling read and write operations and a servo control system forgenerating servo control signals to position the actuator arms 130relative to the disks 104.

FIG. 3A is a perspective view illustrating a first example embodiment ofa disk clamp 240 for use in a hard disk drive assembly of FIG. 2.Further, FIG. 3B is a cross-section view of the first example embodimentof a disk clamp 240 taken along line 3B-3B′.

As illustrated, the clamp 240 has body 246 having a substantiallycylindrical or annular configuration. Threads 242 may be forms on aradially inner surface 244 of the body 246 of the clamp 240. Thesethreads 242 may be configured to engage corresponding threads (notshown) performed on a disk hub 102 (shown in FIG. 2). In someembodiments, the body 246 also includes one or more notches 252 formedin a radially outer surface thereof.

Additionally, a groove 248 is formed in a surface of the body 246. Asillustrated in FIG. 3A, the groove 248 extends in a circumferentialdirection substantially parallel to entire the circumference of the diskclamp 240. However, an exemplary embodiment is not limited to thisconfiguration, and may instead extend substantially parallel to only aportion of the circumference of the disk clamp. In the exampleembodiment illustrated in FIG. 3B, the groove 248 has a quasi-V-shapedcross-section with angled sidewalls 254 and a substantially flat bottom250. However as discussed below other example embodiments are notlimited to this cross-section configuration.

FIG. 4 is a perspective view of the first example embodiment of a diskclamp 240 shown in FIGS. 3A and 3B with a quantity of material added forimbalance correction. FIG. 5 is an enlarged perspective view of aportion 500 of the first example embodiment of a disk clamp 240 shown inFIG. 4 with the quantity of material added for imbalance correction.FIG. 6 is a perspective view of the first example embodiment of a diskclamp 240 with a quantity of material added for imbalance correctionwith the disk clamp cut in half to show a cross-section. FIG. 7 iscross-sectional view of the first example embodiment of a portion 700 ofa disk clamp 240 shown in FIG. 6 with the quantity of material with thedisk clamp cut in half to show a cross-section.

As mentioned above, the clamp 240 is illustrated as having a body 246,threads 242 forms on a radially inner surface 244 of the body 246, and agroove 248 formed in a surface of the body 246. The groove 248 may beprovided to allow balancing of a disk pack of a hard drive using theclamp 240. As shown in FIG. 4, a portion of material 400 has beeninserted into the groove 248 to adjust the mass of the disk pack onwhich the clamp 240 is mounted so as to correct any imbalance in theassembled disk pack.

In the example embodiment of FIGS. 4-7, the portion of material 400 isshown as having a substantially spherical shape. However, an exampleembodiment is not limited to this particular structure and may includealternative structures such as a tear-dropped shaped structure or ahemi-spherical shaped structure. Additionally, in the example embodimentof FIGS. 4-7, the portion of material 400 is shown being positioned inthe center of the groove 248 in contact with the flat bottom 250 of thegroove 248. However, exemplary embodiments are not limited to thisparticular position, and the portion of material 400 may be positionedoffset from the center of the groove in contact with one of the angledwalls 254.

The portion of material 400 is also not limited to a particular materialand may include any clean room approved materials, such as metallicmaterials, resins, plastics, and rubbers. Further, the method of addingthe portion of material 400 is not particularly limited and may includeproviding molten material and allowing it to solidify in place, orplacing a solid material piece, such as a metallic bearing and gluingthe solid piece in place with an adhesive. The method of application ofthe portion of material 400 is discussed in more detail below.

FIG. 8A is a cross-section view of a second example embodiment of a diskclamp 240 for use in a hard disk drive assembly of FIG. 2. FIG. 8B is across-section view of the second example embodiment of a disk clamp 240for use in a hard disk drive assembly of FIG. 2 with a quantity ofmaterial added for imbalance correction.

This second example embodiment has some features similar to those of thefirst example embodiment discussed above and thus similar referencenumerals are used. Specifically, the illustrated clamp 240 has a body246 having a substantially cylindrical or annular configuration, threads242 that may be forms on a radially inner surface 244 of the body 246 ofthe clamp 240. Again, these threads 242 may be configured to engagecorresponding threads (not shown) formed on a disk hub 102 (shown inFIG. 2). Additionally, a groove 848 is formed in a surface of the body246.

Like the first embodiment, the groove 848 in the second embodiment mayextend in a circumferential direction substantially parallel to entirethe circumference of the disk clamp 240. However, an exemplaryembodiment of the present application is not limited to thisconfiguration, and may instead extend substantially parallel to only aportion of the circumference of the disk clamp.

In the first example embodiment shown in FIGS. 3A, 3B, and 4-7, thegroove 248 has a quasi-V-shaped cross-section with angled sidewalls 254and a substantially flat bottom 250. However, as mentioned above,example embodiments of the present application is not limited to thisconfiguration. For example, in the second example embodiment shown inFIGS. 8A and 8B, the groove 848 is formed to have a curved sidewall 850.Specifically, the groove 848 is shown to have a semi-circularcross-section.

Additionally, FIG. 8B, illustrates that a portion of material 400 hasbeen inserted into the groove 848 to adjust the mass of the disk pack onwhich the disk clamp 240 is mounted so as to correct any imbalance inthe assembled disk pack. As in the first embodiment discussed above, theportion of material 400 in the second embodiment is shown as having asubstantially spherical shape. However, an example embodiment is notlimited to this particular structure and may include alternativestructures such as a tear-drop shaped structure or a hemi-sphericalshaped structure.

Additionally, in FIG. 8B, the portion of material 400 is shown beingpositioned in the center of the groove 848 in contact with the curvedsurface 850 of the groove 848. However, example embodiments are notlimited to this particular position, and the portion of material 400 maybe positioned in contact with the curved surface 840 of the groove 848offset from the center of the groove.

Additionally, the portion of material 400 is also not limited to aparticular material and may include any clean room approved materials,such as metallic materials, resins, plastics, and rubbers. Further, themethod of adding the portion of material 400 is not particularly limitedand may include providing molten material and allowing it to solidify inplace, or placing a solid material piece, such as a metallic bearing andgluing the solid piece in place with an adhesive. The method ofapplication of the portion of material 400 is discussed in more detailbelow.

FIG. 9A is a cross-section view of a third example embodiment of a diskclamp 240 for use in a hard disk drive assembly of FIG. 2. FIG. 9B is across-section view of the third example embodiment of a disk clamp 240for use in a hard disk drive assembly of FIG. 2 with a quantity ofmaterial added for imbalance correction.

This third example embodiment has some features similar to those of thefirst example embodiment discussed above and thus similar referencenumerals are used. Specifically, the illustrated clamp 240 has a body246 having a substantially cylindrical or annular configuration, threads242 that may be forms on a radially inner surface 244 of the body 246 ofthe clamp 240. Again, these threads 242 may be configured to engagecorresponding threads (not shown) formed on a disk hub 102 (shown inFIG. 2). Additionally, a groove 948 is formed in a surface of the body246.

Like the first embodiment, the groove 948 in the third embodiment mayextend in a circumferential direction substantially parallel to entirethe circumference of the disk clamp 240. However, an exemplaryembodiment of the present application is not limited to thisconfiguration, and may instead extend substantially parallel to only aportion of the circumference of the disk clamp.

In the first example embodiment shown in FIGS. 3A, 3B, and 4-7, thegroove 248 has a quasi-V-shaped cross-section with angled sidewalls 254and a substantially flat bottom 250. However, as mentioned above,example embodiments of the present application are not limited to thisconfiguration. For example, in the third example embodiment shown inFIGS. 9A and 9B, the groove 948 is formed to have a stepped-sidewallconfiguration having a flat bottom 950 and one or more steps 952, 954.

Additionally, FIG. 9B, illustrates that a portion of material 400 hasbeen inserted into the groove 948 to adjust the mass of the disk pack onwhich the disk clamp 240 is mounted so as to correct any imbalance inthe assembled disk pack. As in the first embodiment discussed above, theportion of material 400 in the third embodiment is shown as having asubstantially spherical shape. However, an example embodiment is notlimited to this particular structure and may include alternativestructures such as a tear-drop shaped structure or a hemi-sphericalshaped structure.

Additionally, in FIG. 9B, the portion of material 400 is shown beingpositioned in the center of the groove 948 in contact with one or moreof the steps 952, 954 formed in the groove 848. However, exampleembodiments are not limited to this particular position, and the portionof material 400 may be positioned in contact with one or more of thesteps 952, 954 offset from the center of the groove.

Additionally, the portion of material 400 is also not limited to aparticular material and may include any clean room approved materials,such as metallic materials, resins, plastics, and rubbers. Further, themethod of adding the portion of material 400 is not particularly limitedand may include providing molten material and allowing it to solidify inplace, or placing a solid material piece, such as a metallic bearing andgluing the solid piece in place with an adhesive. The method ofapplication of the portion of material 400 is discussed in more detailbelow.

FIG. 10A is a cross-section view of a fourth example embodiment of adisk clamp 240 for use in a hard disk drive assembly of FIG. 2. FIG. 10Bis a cross-section view of the fourth example embodiment of a disk clamp240 for use in a hard disk drive assembly of FIG. 2 with a quantity ofmaterial added for imbalance correction.

This fourth example embodiment has some features similar to those of thefirst example embodiment discussed above and thus similar referencenumerals are used. Specifically, the illustrated clamp 240 has a body246 having a substantially cylindrical or annular configuration, threads242 that may be forms on a radially inner surface 244 of the body 246 ofthe clamp 240. Again, these threads 242 may be configured to engagecorresponding threads (not shown) formed on a disk hub 102 (shown inFIG. 2). Additionally, a groove 1048 is formed in a surface of the body246.

Like the first embodiment, the groove 1048 in the fourth embodiment mayextend in a circumferential direction substantially parallel to entirethe circumference of the disk clamp 240. However, an exemplaryembodiment of the present application is not limited to thisconfiguration, and may instead extend substantially parallel to only aportion of the circumference of the disk clamp.

In the first example embodiment shown in FIGS. 3A, 3B, and 4-7, thegroove 248 has a quasi-V-shaped cross-section with angled sidewalls 254and a substantially flat bottom 250. However, as mentioned above,example embodiments of the present application are not limited to thisconfiguration. For example, in the fourth example embodiment shown inFIGS. 10A and 10B, the groove 1048 is formed to have a saw-toothedcross-section with an inclined bottom 1050. Additionally, in someembodiments, a protruding member 1052 may extend toward the center ofthe groove from a sidewall 1054.

Additionally, FIG. 10B, illustrates that a portion of material 400 hasbeen inserted into the groove 1048 to adjust the mass of the disk packon which the disk clamp 240 is mounted so as to correct any imbalance inthe assembled disk pack. As in the first embodiment discussed above, theportion of material 400 in the fourth embodiment is shown as having asubstantially spherical shape. However, an example embodiment is notlimited to this particular structure and may include alternativestructures such as a tear-drop shaped structure or a hemi-sphericalshaped structure.

Additionally, in FIG. 10B, the portion of material 400 is shown beingpositioned in the center of the groove 1048 in contact with the inclinedbottom 1052 of the groove 1048. However, example embodiments are notlimited to this particular position, and the portion of material 400 maybe positioned offset from the center of the groove 1048.

Additionally, the portion of material 400 is also not limited to aparticular material and may include any clean room approved materials,such as metallic materials, resins, plastics, and rubbers. Further, themethod of adding the portion of material 400 is not particularly limitedand may include providing molten material and allowing it to solidify inplace, or placing a solid material piece, such as a metallic bearing andgluing the solid piece in place with an adhesive. The method ofapplication of the portion of material 400 is discussed in more detailbelow.

FIG. 11 is a perspective view illustrating an example apparatus applyingthe quantity of material to an example embodiment of a disk clamp 240.

As illustrated, an apparatus 1100 for applying a quantity of material400 to an example embodiment of the disk clamp 240 includes a supplymaterial unit 1102, a control device (such as a PC or controller) 1104,a pressure/time unit 1106, and an injection nozzle 1108 from which thequantity of material 400 is supplied. Specifically, the control device1104 is connected and controls the pressure/time unit 1106 and thesupply material unit 1102. Further, the injection nozzle 1108 is alsoconnected to the pressure/time unit 1106 and the supply material unit1102. The control device 1104 causes the supply material unit 1102 tosupply a predefined amount of material to the injection nozzle 1108 whenthe injection nozzle 1108 is positioned proximate to an area of thegroove 248 of the clamp 240 to which the quantity of material 400 is tobe provided. Further, the control device 1104 also causes thepressure/time unit 1106 pressure to the injection nozzle 1108 for adefined period of time such that the quantity of material provided bythe supply material unit 1102 is propelled out of the injection nozzle1108 and into the groove 248 of the clamp 240 to form the quantity ofmaterial 400.

Optionally, in some embodiments, the apparatus 1100 may also include anenergy unit 1110 that provides energy to the material supply unit 1102to melt the supply material into a molten state, prior to the supplymaterial unit 1102 providing the quantity of material to the injectionnozzle 1108. The energy unit 1110 may be a laser unit, heating unit, orany other type of unit that can be used to reduce a quantity of materialto a molten state. In these embodiments, the supply material unit 1102supplies the quantity of material in a molten state, which solidifies toform the quantity of material 400 in the groove the groove 248 of theclamp 240. By controlling the amount of material provided to theinjection nozzle 1108, the pressure supplied by the pressure/time unit1106, and the time over which the pressure is applied, the control unit1104 may control the size of the quantity of material 400 injected intothe groove 248. In some embodiments, the quantity of material 400 may be100 microns in size.

However, the apparatus 1100 shown in FIG. 11 is not the only embodimentof an apparatus that can be used to provide quantity of material 400into the groove 248 of the clamp 240. Further, the energy unit 1110 maybe omitted in some embodiments. For example, an alternative apparatusmay involve a movable XY stage that may place solid pieces of materialinto the groove 248, and a laser which causes the solid piece ofmaterial to become partially melted and secured in place. Further,another alternative apparatus may involve a movable XY stage that mayplace solid pieces of material into a portion of adhesive applied withinthe groove 248 by an injection nozzle similar to injection nozzle 1108,allowing the adhesive to hold the solid piece of material in place.Other alternative apparatuses may be apparent to a person of ordinaryskill in the art.

FIG. 12 illustrates a flow chart for a method 1200 of manufacturing adisk drive, according to at least one illustrated embodiment. Thismethod 1200 will be discussed in the context of the hub 102 and the diskclamp 240 of FIGS. 2-7 and 11. However, the acts disclosed herein may beexecuted using a variety of different disk hubs and disk clamps, inaccordance with the described method. For example, the acts disclosedherein may alternatively be executed using the hub 102 and the diskclamp 240 of FIGS. 8A-10B.

As described herein, at least some of the acts comprising the method1200 may be orchestrated by a processor according to an automatic diskdrive manufacturing algorithm, based at least in part oncomputer-readable instructions stored in computer-readable memory andexecutable by the processor. A manual implementation of one or more actsof the method 1200 may also be employed, in other embodiments.

At act 1210, a disk hub 102, a disk 104 and a disk clamp 240 areprovided. The hub 102 may define a mounting surface (not labeled) and acylindrical portion 108 having a vertical surface 202. In someembodiments, a plurality of threads may be formed in the verticalsurface of the hub 102.

The disk clamp 240 may define a body 246, which in some embodiments mayhave a plurality of threads 242 formed on a radially inner surfacethereof. Additionally, a groove 248 is formed in a surface of the body246. Further, in some embodiments, the groove 248 extends in acircumferential direction substantially parallel to entire thecircumference of the disk clamp 240. However, an exemplary embodiment isnot limited to this configuration, and may instead extend substantiallyparallel to only a portion of the circumference of the disk clamp.Further, in the example embodiment illustrated in FIG. 3B, the groove248 has a quasi-V-shaped cross-section with angled sidewalls 254 and asubstantially flat bottom 250. However, the groove 248 may havealternative structures, such as the example structures shown in FIGS.8A-10B.

The disk 104 may define an opening there through having an innerdiameter. The disk 104 may be formed in a variety of ways. In oneembodiment, the media of the disk 104 may be formed, and then the disk104 may be stamped or otherwise machined to define the first opening.

The hub 102 may also be formed in a variety of ways. In one embodiment,the hub 102 may be machined to form the mounting surface, thecylindrical portion 108 and the vertical surface. In other embodiments,the hub 102 may be cast, molded or machined to form the mounting surfaceand the vertical surface. In still other embodiments, othermanufacturing techniques may be employed.

Similarly, the manufacturing method of the disk clamp 240 is notparticularly limited and may include machining, casting, molding, or anyother methods as would be apparent to a person of ordinary skill in theart.

At act 1215, the disk 104 is positioned against the mounting surface ofthe hub 102. The cylindrical portion 108 of the hub 102 may be insertedthrough the opening formed in the disk 104 and the disk 104 may bepositioned in physical contact with the mounting surface. In someembodiments, a machine vision system may help align the disk 104 and themounting surface of the hub 102.

At act 1220, the disk clamp 240 is coupled to the disk hub 102 toprovide a clamping force to the disk 104. Specifically, in theembodiment shown in FIGS. 3-7, the cylindrical portion 108 of the hub102 may be inserted into the opening of the annularly shaped disk clamp240. Further, in an embodiment of the disk clamp 240 having threads 242formed on a radially inner region 244, the threads 242 may engagethreads forms on the vertical surface of the cylindrical portion 108 ofthe hub 102. Further, the threads 242 of the disk clamp 240 may berotated downward along the threads of the hub 102 until the disk clampengages the disk 104 to provide a clamping force thereto.

At act 1225, after the disk clamp to 40 is coupled to the disk hub 102to write a clamping force to the disk 104, imbalance of the disk packassembly is measured to collect imbalance data for the assembled diskpack using methods that would be apparent to a person of ordinary skillin the art.

At act 1230, using the collected imbalance data, an amount of materialand orientation, in three dimensions, necessary to correct the imbalanceof the disk pack assembly is calculated using methods that would beapparent to a person of ordinary skill in the art.

At act 1235, a portion of material 400 is positioned at the requiredorientation to correct the imbalance of the disk pack assembly.Specifically, the portion of material 400 is positioned at a locationwithin the groove 248 of the clamp 240 there was calculated in act 1230as the necessary location to correct the imbalance calculated in act1225. If the groove 248 extends parallel to the entire circumference ofthe clamp 240, the portion of material 400 can be positioned anywherearound the groove 248 to allow finer control of the placement of theportion of material 400 as compared to an embodiment that has a groove248 that only extends parallel to a portion of the circumference of theclamp 248. Further, if the groove 248 has angular sidewalls 254, acurved bottom 850, a plurality of steps 952, 954, or an angled bottom1050, as shown in FIGS. 3B, 8B, 9B, 10B, the vertical placement of theportion of material 400 may also be controlled to allow the imbalance ofthe disk pack assembly to be corrected in three dimensions bypositioning the portion of material 400 at different positions both avertical and horizontal directions.

The placement of the portion of material may be performed by an applyingapparatus such as the apparatus shown in FIG. 11. Using an apparatus,such as the apparatus shown in FIG. 11, the injection nozzle 1101 may bepositioned proximate to the area of the groove 248 to which the portionof the material 400 is to be added. As discussed above, the controldevice 1104 could then cause the supply material unit 1102 to supply apredefined amount of molten material to the injection nozzle 1108 andalso cause the pressure/time unit 1106 pressure to the injection nozzle1108 for a defined period of time to propel the supplied material out ofinjection nozzle and into the groove 248 of the clamp 242 to form thequantity of material 400.

However, an example method need not use the apparatus shown in FIG. 11,or any other apparatus. Additionally, the quantity of material 400 neednot be provided in a molten state and instead could be a pre-formedportion of material that is attached to the groove 248 by adhesive.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, schematics,and examples. Insofar as such block diagrams, schematics, and examplescontain one or more functions and/or operations, each function and/oroperation within such block diagrams, flowcharts, or examples can beimplemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof. Inone embodiment, the present subject matter may be implemented viaApplication Specific Integrated Circuits (ASICs). However, theembodiments disclosed herein, in whole or in part, can be equivalentlyimplemented in standard integrated circuits, as one or more programsexecuted by one or more processors, as one or more programs executed byone or more controllers (e.g., microcontrollers), as firmware, or asvirtually any combination thereof.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the protection. Indeed, the novel methods and apparatusesdescribed herein may be embodied in a variety of other forms.Furthermore, various omissions, substitutions and changes in the form ofthe methods and systems described herein may be made without departingfrom the spirit of the protection. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of the protection.

What is claimed is:
 1. A disk drive assembly comprising: a disk hub; adisk media; and an annular disk clamp that engages a radial surface ofthe disk hub to couple the disk media to disk hub, wherein the diskclamp comprises: a body portion having a transverse hole extendingthrough the body portion; and a groove formed in a surface of the bodyportion and extending in a circumferential direction substantiallyparallel to at least a portion of the circumference of the disk clamp;and a balance weight installed in the groove formed in the surface ofthe disk clamp, wherein the balance weight comprises a quantity ofmaterial applied in the groove.
 2. The disk drive assembly according toclaim 1, wherein the groove has a substantially semi-circular crosssection.
 3. The disk drive assembly according to claim 1, wherein thegroove has a cross-section comprising one or more steps formed on abottom thereof.
 4. The disk drive assembly according to claim 1, whereinthe groove has a cross-section comprising an inclined bottom.
 5. Thedisk drive assembly according to claim 4, wherein the groove comprises aprotrusion that extends from a radially inner wall of the groove towardthe center of the groove.
 6. A disk clamp configured to engage a diskhub to couple a disk media to a disk hub, wherein the disk clampcomprises: an annular body portion having a transverse hole extendingthrough the body portion, the body portion configured to engage a radialsurface of the disk hub; and a groove formed in a surface of the bodyportion and extending at least in a circumferential directionsubstantially parallel to at least a portion of the circumference of thedisk clamp; and a balance weight installed in the groove formed in thesurface of the disk clamp, wherein the balance weight comprises aquantity of material applied in the groove.
 7. The disk clamp accordingto claim 6, wherein the groove has a substantially semi-circular crosssection.
 8. The disk clamp according to claim 6, wherein the groove hasa cross-section comprising one or more steps formed on a bottom thereof.9. The disk clamp according to claim 6, wherein the groove has across-section comprising an inclined bottom.
 10. The disk clampaccording to claim 9, wherein the groove comprises a protrusion thatextends from a radially inner wall of the groove toward the center ofthe groove.
 11. A method of balancing a disk pack in a disk drive, themethod comprising: providing a disk media, a disk hub and a disk clamphaving a circumferentially extending groove formed in a surface thereof;positioning the disk media proximate to the disk hub; coupling the diskclamp to the disk hub to apply a clamping force to the disk media;determining an imbalance of the coupled disk clamp, disk hub, and diskmedia; and attaching a quantity of material so as to be in a stationaryposition within the groove to correct the imbalance.
 12. The methodaccording to claim 11, wherein the attaching a quantity of materialcomprises inject a quantity of molten material into the groove.
 13. Themethod according to claim 12, wherein the quantity of molten material isinjected into the groove using jet printing.
 14. The method according toclaim 11, wherein the attaching a quantity of material comprisesattaching a bearing to the groove using adhesive.
 15. The methodaccording to claim 11, wherein the groove has an inclined surface; andwherein the attaching a quantity of material into the groove comprises:positioning the material along the inclined surface to correct theimbalance in three-dimensions.
 16. The method according to claim 11,wherein the groove has a cross-section having one or more steps formedon a bottom thereof; and wherein the attaching a quantity of materialinto the groove comprises: positioning the material on the one or moresteps formed on a bottom of the groove to correct the imbalance inthree-dimensions.